Mode Shapes Evaluation of Trunk Shakers Used in Oil Olive Harvesting

Abstract

Trunk shakers are used for the mechanical harvesting of olive fruits for oil production. Although trunk shakers are widely used, they can damage the tree's bark due to slippage generated between the shaker and the trunk during the shaking process. The aim of this research is to perform a dynamic analysis of trunk shakers and study the possible resonance phenomena. Dynamic analysis of the shaker was performed by clamping the machine to a shaker-post system. The results showed the existence of rotational rigid body modes at low frequencies. Subsequently, field tests were performed to determine the operational frequency range of the shaker (20 to 40 Hz). This frequency range was found to be between the natural frequencies of the first and second modes. A resonance situation was detected in one shaker, as the second mode shape (Z-axis rotation) coincided with its operational frequency range (23.6 Hz).